This invention relates generally to off-set mowers and more particularly to off-set mowers which are attached to the side of a tractor or other vehicle.
It is known in the prior art to mount a mower or other implement on the side of a tractor or other vehicle for cutting grass or weeds on inclined slopes and inaccessible places. Such a side mounted mowers allow mowing of drainage ditches and the like where a tractor cannot be driven. Such side mounted mowers are used extensively where a conventional rear mounted mower cannot be safely operated.
It is also been known in the prior art to provide a breakaway mechanism to allow the mower to be released upon striking an obstacle to avoid damage to the mower mounting apparatus. Examples of such devices are disclosed in the following U.S. Pat. Nos. 2,729,044; 2,840,974; 3,135,079; 3,472,006; 3,526,083; and 3,664,057. In particular, U.S. Pat. No. 3,472,006 issued to T. J. Dunn discloses a break-away design for a mower which mounts the mower about a generally vertical pivot pin and retains the mower from breaking away or pivoting with a hook member having a detent. When the mower strikes an object, the mower is allowed to rotate about the pivot pin upon overcoming the retaining force of the retaining member. The mower is returned to its operating position through a hydraulic cylinder and a loss motion linkage system. Another example of a releasing or break-away system for a mower is shown in U.S. Pat. No. 3,664,057 also issued to T. J. Dunn. This mechanism also mounts the mower at the distal ends of the linkage system for rotation about a generally vertical axis. A coil-type spring is used to retain the mower in its operating position and to allow rotation of the mower about the vertical pivot axis upon engaging or striking an obstacle. An example of the operation of the pivoting mechanism in U.S. Pat. No. 3,664,057 is shown in U.S. Pat. No. 3,135,079 also issued to T. J. Dunn. In FIG. 12 of U.S. Pat. No. 3135079 the mower is shown rotated about its pivot axis upon engaging an obstacle. The amount of force necessary to affect the break-away mechanism for U.S. Pat. Nos. 3,135,079; 3,472,006 and 3,664,057 is different depending upon the location at which the mower strikes an obstacle. As will be apparent when the mower strikes an obstacle at a lateral most position of the mower there is a large effective lever arm to affect movement of the break-away mechanism. However, when the mower strikes an obstacle positioned much closer to the break-away mechanism, then a larger force will be exerted on the mower due to the greatly decreased effective lever arm. Another type of mower which utilizes a side mounting apparatus are the so-called boom mowers, examples of which are shown in U.S. Pat. Nos. 3,221,482; 3,236,036 and 3,949,539. Each of these patents mounts a boom for rotation about a generally vertical axis and provides a hydraulic cylinder for affecting rotation of the boom. A relief valve is provided in the hydraulic circuitry for the boom rotating cylinder so that when the mower which is attached to the outer end of the boom strikes an obstacle the boom will be allowed to rotate about its pivot axis backwardly to avoid damage to the apparatus.
So far as known, many attempts have been made to solve the long existing problem of providing a safety release for a side mounted mower to prevent damage to the mower when it strikes an obstacle. The known apparatuses discussed above have provided for rotation of the mower about a generally vertical axis in response to the mower striking an obstacle. It is an object of this invention to solve the problems of providing a safety release for a mower which would allow the mower to translate without requiring rotation of the mower to overcome the problems of prior art devices and provide a mower which can be safely and effectively used without damage to the mower.